Exhaust gas emitted from an internal combustion engine, particularly a diesel engine, is a heterogeneous mixture that contains gaseous emissions such as carbon monoxide (“CO”), unburned hydrocarbons (“HC”) and oxides of nitrogen (“NOx”) as well as condensed phase materials (liquids and solids) that constitute particulate matter. Catalyst compositions typically disposed on catalyst supports or substrates are provided in an engine exhaust system to convert certain, or all of these exhaust constituents into non-regulated exhaust gas components.
Particulate filters (“PF”) remove the particulate matter from the exhaust gas. The particulate matter accumulates within the PF. The accumulated particulate matter causes an increase in exhaust system backpressure experienced by the engine. To address this increase, the PF is periodically cleaned, or regenerated. Regeneration of a PF in vehicle applications is typically automatic and is controlled by an engine or other controller based on signals generated by engine and/or exhaust system sensors.
Accordingly, it is desirable to provide systems and methods for monitoring the frequency of regenerating a PF.